The present invention relates generally to sign holders and, more particularly, to a sign holder for temporary use along railway lines.
Temporary sign holders are used to alert railway personnel, particularly locomotive operators, as to unsafe track conditions, and the presence of personnel and equipment working in proximity to an active track. The use of electronic signaling equipment is known, however, such electronic devices are expensive both to install and maintain on a permanent basis. As a result, track areas within some railway systems are unserviced by signaling devices and therefore cannot warn approaching trains with respect to the existence of temporary speed restrictions, workers and equipment working in proximity to the tracks, and other conditions generally considered unsafe for railway traffic.
Governmental regulations require the presence of temporary warning devices positioned at appropriate places to advise train operating personnel of hazardous and possibly unsafe conditions that are being approached. For that purpose, temporary flagging devices are embodied in different forms. For example, one type of temporary flagging device is simply driven into the ground or ballast material. One of the problems associated with these temporary flagging structures is that two workers are required to install the device. Typically, one worker holds the flagging device while the other worker wields a sledge hammer to drive the device into the supporting ground or structure. This prior art approach utilizes excessive manpower, requires both considerable time to both drive the temporary flagging device into the supporting structure and remove the same after the intended use. This is because the track is often laden with rocks or may also be frozen which makes it difficult to properly apply the temporary flagging device.
Since train operating personnel must rely upon such temporary flagging devices, it is critical that these devices remain in situ throughout the entire period of intended use. One major problem involves the virtual impossibility of maintaining these temporary devices in proper flagging position, due to human factors, such as vandalism and theft, and environmental factors, such as wind, erosion, earthquakes, animals, flooding, etc. These problems are exacerbated due to the requirement that the flagging device be sufficiently lightweight and portable to enable easy transit to the installation site.
U.S. Pat. Nos. 1,320,380 and 1,361,308, both to A. L. Currie, disclose railway flagging devices that are operatively mounted to one of the rails with a clamping arrangement to which is attached a tubular member projecting upwardly and outwardly away from the rail to support signage. The clamping member essentially includes a clamping base terminating at one end in a U-shaped flange adapted to embrace one edge of a lower flange of the rail. A clamping member is slidably mounted to the base to abut against the opposite lower flange of the rail. A bolt connecting the clamping member to the base is tightened to exert a downward force acting perpendicular to the lower flange of the rail to press the clamping member thereagainst. Similar clamping arrangements are also disclosed in U.S. Pat. No. 5,038,704 to Dean et al wherein a wing nut and bolt combination are provided to exert a downward force against a clamping plate engaging the upper surface of one of the lower flanges of the rail.
One of the problems associated with these prior art track engaging components is that they are not structured or designed to withstand strenuous track conditions as created by modern day rail systems and are therefore inherently susceptible to mechanical failure. For example, the tremendous vibration transmitted through the rail to the clamping mechanism as a result of train passage has the capability of gradually loosening the clamping member pressing against the lower flange, creating an unsafe condition. Additionally, the amount of clamping force provided by these prior art clamping systems is low since these systems are incapable of being initially tightened to a degree that provides a high degree of clamping capable of resisting tampering or certain types of environmental conditions.
It is accordingly an object of the present invention to provide a temporary sign holder that can be non-destructively attached to a rail with a high degree of clamping force.
Another object is to provide a temporary sign holder capable of maintaining an appropriate train clearance envelope.
Still another object is to provide a temporary sign holder that is safe for employees to work around.
Yet another object is to provide a sign holder that is tamper proof and capable of easy installation and removal with minimal maintenance crew (e.g., one worker).
The present invention is directed to a temporary sign holder attachable to a rail base which projects from opposite sides of a rail web supporting a rail head to provide a support for temporary signage observable by both train operating personnel and maintenance personnel. The holder comprises a support base and a post connected to the support base to extend outwardly away from the rail and support signage. To firmly mount the temporary sign holder to the rail, the temporary sign holder includes first and second clamps interconnected to each other and being formed with angled or curved clamping sections that respectively engage opposite parallel lower flanges of the rail base. A tightening mechanism interconnecting the first and second clamping members is manually operated to move the clamping members towards each other into progressively tighter clamping contact with the rail base. The temporary sign holder is advantageously supported by the rail itself in such a manner so that it will effectively maintain signage at a proper position throughout the duration of its intended use. The design, construction and cooperative inter-relationship of the elements reduces risks of mechanical damage or operational failure and is easily transportable and installable through the efforts of one worker.
The first clamping member preferably includes a first clamping rod that is hooked at one end thereof and threaded at the opposite end. The second clamping member is preferably formed with a plate having a curved or angled section along one edge. A surface of the plate supports a hollow sleeve that is open at opposite ends thereof to permit entry and passage of the first clamping rod therethrough. In operative position, the threaded end of the first clamping rod extends from the sleeve to receive a nut that is rotatable to urge the clamps towards each other into progressively tighter clamping contact with the rail base.
In the preferred embodiment, the nut is formed on a circular plate having a relatively large diameter of one to four inches. By providing a large diameter circular plate, the worker can easily grasp and rotate the plate to turn the nut with sufficient torque to effectively install the sign holder to the rail with appropriate clamping force.
In accordance with a further feature of the preferred embodiment, the nut is located in the center of the tightening plate. A plurality of circumferentially spaced openings are located for selective alignment with a corresponding opening formed in a mounting tab attached to the sleeve. After the circular plate is tightened with sufficient force, the worker ensures that one of the plate holes is in alignment with the tab opening to thereby enable installation of a lock to protect the installed holder from acts of vandalism, theft or other unauthorized trespass.
A method of temporarily securing signage to a railway rail is also disclosed. The method comprises the steps of loosely mounting first and second clamps to opposite longitudinally extending lower flanges of a rail base by passing one of the clamps beneath the rail into contact with an inward facing one of the flanges. The clamps are then tightened together with a tightening mechanism having a clamping axis extending transversely to the rail longitudinal axis.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein only the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive.